1. Field of the Disclosure
The present disclosure relates to reclosable packages or bags that can be filled through the top of the package. The present disclosure further relates to the use of a perforated line or other line of weakness in a large capacity or high burst zipper in order to facilitate a fill-behind-the-zipper operation.
2. Description of the Prior Art
In the prior art, reclosable packages or bags have typically been filled two ways. The first is through the open zipper. However, this may not be practical in reclosable packages which use tamper evident structures, such as frangible panels, peel seals or high burst barriers between the zipper profiles and the package interior. Additionally, filling through the zipper may be problematic if a removable shroud over the top of the zipper is desired. A second method of filling through the top of the package is to leave the flange of one of the zipper halves unattached to one wall of the bag and to fill the bag between the zipper flange and the bag wall. However, this may be disadvantageous in that the final zipper-to-bag seal must be made in the location of the filling operation, which may be remote from the location where the bag was originally manufactured. Additionally, making the zipper-to-bag seal can be problematic in that the zipper and bag material are often made from incompatible materials, such as when a polyethylene zipper is mated to a multi-wall paper bag (MWPB) or to a woven polypropylene bag (wPP). In such an instance, the fill time is greatly increased due to required cooling times for hot melt glue systems. In other instances, long dwell times for heat or ultrasonic welding may be required.
Large reclosable packages and the methods of manufacture thereof are disclosed in commonly assigned U.S. Pat. No. 7,963,007, issued on Jun. 21, 2011, entitled “High Burst Zipper Assembly for Large Reclosable Packages”; U.S. Pat. No. 7,621,105, issued on Nov. 24, 2009 entitled “Method of Producing High Burst Zipper Assemblies for Large Reclosable Packages” and U.S. published application no. 2008/0047228, published on Feb. 28, 2008, entitled “Hot-Melt Adhesive Systems for Zipper Assemblies on Large Bag Constructions of Various Substrates”. As stated above, while these large reclosable packages have been found to be suitable for their intended uses, further improvements may be sought in designing these packages with respect to filling these packages from the top. In particular, these references disclose that a separate strip of polyethylene material may be attached to the bag wall and one half of the zipper is left unconnected to the bag. Product is filled between the polyethylene strip and the zipper and then the zipper and strip are joined together to seal the bag. However, this method requires that an additional strip of polyethylene be supplied along with the zipper, adding cost and complicating bag construction.